|Source||defeating Bubble Blade|
Grenade was a type of explosive that could be picked up after defeating Bubble Blade for the first time in one of the rooms on the 3rd floor.
If you try to use it Carnby will refuse, commenting "You don't want me to blow everything up!" . It can only be thrown into the chimney pipe that connects the penthouse to the room full of zombie gangsters on the ground floor. Once thrown, in fact, it will kill the two guards capable of killing with a single shot, but leaving all the other enemies alive.